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2014 Mercedes-Benz S63 AMG, 2014 Jaguar XJR, 2015 Audi S8 Review

We’ve brought together the quickest and most powerful V-8 variants of three of the most desirable and prestigious full-size luxury sedans in the world, the Audi A8, the Jaguar XJ, and the Mercedes-Benz S-Class. In doing so, we have stuck with the assumption that the essence of old-fashioned, white-knuckle, temple-throbbing driving pleasure in the year 2014 is still composed of howling V-8 engines, flickering stability control warning lights, and a lust factor that grows in proportion with revs, acceleration, and speed. The Audi S8, the Jaguar XJR, and the Mercedes S63 AMG 4Matic have no interest in stitching up the yawning hole in the ozone layer, in saving baby whales or rain forests, or in setting a shining example of social responsibility and self-denial. Quite the contrary: in this particular seventy-two-hour contest, we staked out a remote, radar-free environment and targeted a set of breathtaking primary and secondary roads where we could drive the rubber socks off of three remarkable, 500-plus-hp, high-performance boardroom haulers on a no-holds-barred tour de force of rural Upper Bavaria, Salzburg, and Tyrol.

Although the 577-hp S63 eclipses the XJR by 27 hp and the S8 by 57 hp, the mean-looking Merc is actually quite jovial and obliging in character. Its big-bore twin-turbo engine runs so smoothly and quietly, you might think you’re wearing a pair of wax earplugs. Throttle response even in sport mode is relatively restrained and relaxed, the transmission rides the torque surf in seven subtle steps, the suspension is firm yet supple, and the sound-deadening materials give the term “splendid isolation” a whole new meaning. Whereas the eight-speed automatics used by Audi and Jaguar will shift up with near-whiplash force and lightning-like speed in sport mode, the Benz changes gears with rapid fluency and velvet-glove urgency. Despite these gentlemanly manners, the S63 can accelerate to 60 mph in 3.9 seconds with no trace of takeoff wheelspin, up to 664 lb-ft of physical punch between your shoulder blades, and only one gearchange.

The Audi, too, benefits from the traction bonus only four-wheel drive can provide. Against the stopwatch, the S8 is equal to the bigger and heavier Mercedes, according to their manufacturers. On slippery surfaces, through tight corners, and at the start of every traffic-light grand prix, both German contenders compete in a league of their own. In winter, only the rear-wheel-drive Jaguar struggles on icy on-ramps, when tackling snow-covered climbs, while easing into and out of unplowed roadside parking spots, or when attempting to merge with fast traffic. Fitted with a 4.0-liter twin-turbo V-8 redlined at 6400 rpm, the Audi is between five and ten percent more economical than the other two V-8-powered sedans. During our test drives, it averaged 17 mpg versus the Jaguar’s 15 mpg and the S63’s 16 mpg. In terms of sheer power and torque, however, the S8 (520 hp, 481 lb-ft) cannot quite match the XJR (550 hp, 502 lb-ft) or the even brawnier S63 AMG (577 hp, 664 lb-ft).

Even though the Audi has the best fit and finish, the classiest instruments, the most tasteful interior, and the brightest headlights (full LEDs in this case), the four rings don’t signify perfection in every respect. The MMI infotainment system, for instance, gets more complex with every round of modifications; access to the extensive Drive Select menu should be more intuitive; and the Tiptronic gear selector often needs two or three attempts to engage and stay in reverse. Standard equipment includes 21-inch wheels, air suspension with a sporty calibration, dynamic steering, a sport differential, a navigation system, and leather upholstery. You must pay extra for carbon-ceramic brakes, night vision, and most driver-assistance systems. The Audi has the smallest trunk (13.2 cubic feet) and the biggest tank (23.8 gallons), which grants it the longest range. The trunk of the Benz measures 16.3 cubic feet, while that of the Jaguar holds 15.2 cubic feet. All three cars ran on winter tires for this test. Our European-spec S8 was shod with 265/40R-20s all around; the XJR made do with downsized 245/45R-19s in front and 275/40R-19s at the back (twenties are standard); and the S63 was delivered with 255/40R-20s front, 285/35R-20s rear.

The Jaguar’s cabin is a nice mix of Buckingham Palace tradition and Silicon Valley modernity. At a glance, the XJR appears fully loaded. The cabin accents are fabricated of piano black and glossy metal; hide and suede covers everything else. The usual conveniences are paired with a decent sound system. When you zoom in and compare, though, the 550-hp Briton won’t let you specify as many high-tech options as its German challengers. Even adaptive cruise control costs extra. The charmless digital instruments look out of place in such an upmarket environment, and the dynamic have-fun goodies are limited to a more lenient in-between stability control setting, an on-demand firmer spring and damper tuning, and quicker transmission software. There’s no head-up display, no composite brake discs, and—perhaps most significant—no available all-wheel drive, which can be ordered only with the V-6 XJ.

The Euro-spec, standard-wheelbase, rear-wheel-drive S63 AMG comes with Magic Body Control, Mercedes-speak for two cameras that scan the road surface to alert the suspension before it encounters obstacles such as potholes or transverse ridges. The long-wheelbase S63 AMG 4Matic, the only S63 offered in America (and the version we tested in Europe), is equipped with a spiced-up variant of the Airmatic air suspension. Other S63 ingredients include stronger brakes, a more attentive Speedshift transmission, more direct steering, and the ability to select sportier drive modes. In addition, the S63 has the full go-faster treatment: the seats have special leather, stitching patterns, piping, and emblems; the stylish body kit should be as good at reducing drag as it is at turning heads; the four gleaming tailpipes are almost as big in diameter as foxholes; and, to avoid confusion with lesser Benzes, there are about two dozen AMG logos prominently scattered throughout the car. So far, so good. But when you put the S63 to the real test by waltzing through a set of hold-your-breath curves, a larger than expected portion of the promised sparkle is lost in translation. In sum, the cream-of-the-crop Mercedes actually dishes up a less invigorating menu than the loud and loose XJR. The S63 AMG is a complete and competent car, but it has been wrapped in too many neutralizing layers of cotton wool.

After almost 600 demanding miles, the Mercedes emerged as a luxury limousine with degrees in velocity, ride comfort, and stability. In this features-galore mile-eater, the driver is constantly tailed by a battalion of electronic helpers that know how and when to stay in the lane, keep the correct distance, decelerate in an emergency, pull at the steering wheel if need be, and park the car automatically. Although fully autonomous driving is one of the brand’s declared goals, the S63 thankfully still expresses interest in such AMG priorities as handling and roadholding, cornering grip and steering accuracy, brake bite and throttle response. The steam-hammer version turns in more eagerly than the S550, decelerates with added vigor, handles with greater talent, is a true champion of acceleration, and can be coaxed into feeling quite chuckable for a behemoth weighing 4806 pounds. Despite all that, the 5.5-liter hypersedan feels too much like a very fast S-class and not enough like a raw and special driving machine prepared by the most talented power brokers in the trade. The smaller E63 AMG is much sharper and more communicative, a superior master of quick escapes and grand gestures.

The Jaguar epitomizes the very British art of waftability, but refined part-throttle cruising and posing at street-café pace are not its only skills. When asked to give chase, the XJR will instantly change down a gear or two, expertly flex and stretch its muscles, then slowly lower its head and aim at the horizon with the energy of a sprinter who has somehow managed to adopt the delicate balance of a high-wire performer. Be content to relish the car’s communication skills this side of burn-outs and tail slides, and the XJR may become an ally, perhaps a friend. But if whips and spurs are your thing, the Jag is liable to mutate from house cat to wildcat. The instant James the devoted chauffeur hands the keys to his alter ego Zorro the racer, the car’s personality and attitude undergo a dramatic change. From one moment to the next, supercharger whine and exhaust trumpets set the tone, the nineteen-inch winter tires struggle to connect even on clear blacktop, and the quick steering develops a newfound lightness.

The limit arrives earlier and more suddenly than expected, and when it does, the Jaguar is notably more difficult to keep on course than the S8 or the S63. The paddle-operated gearbox isn’t totally composed, either. In sport mode, it feels more like a dual-clutch automatic than like the torque-converter automatic it is, holding on to a given ratio all the way to the engine’s redline and then shifting with time-warp efficiency. The brakes bite with such unyielding force that one would not be surprised if the pads were basted with piranha teeth. Every acceleration from 50 to 75 mph leaves a deep dimple in the pit of your stomach, and the growling V-8 is inherently aggressive. All of which is another way of saying that this Jaguar is a very special animal, competent and controversial yet flawed in a quite charming way.

To summarize, the Jaguar is a great plaything for the twenty-mile Saturday-morning detour to the bakery and coffee house but leaves something to be desired as an all-weather 24/7 executive runabout; the Mercedes just does not have the same effect on our heart rate, blood thickness, and adrenaline flow as most other AMG products. Which brings us to the Audi S8 and its stature in this trio.

While the sporty S8 has great potential, it is not available in long-wheelbase form, so tall rear-seat occupants struggle for space. On a good day, one may be tempted to describe the design as classic, but when you take off the rose-colored glasses, the aging cookie-cutter single-frame grille is inexpressive and ordinary. In theory, the driving dynamics should be spot-on, and yet in real life they form an odd mix of highs and lows. Take the handling, which ranges from defensive to indifferent, all the way from casual cornering exercises to terminal understeer at the very edge of adhesion. Feel the steering, which refuses to feed your palms with enough weight, self-centering action, and grip information. Try the brakes, which are very powerful and totally immune to fade but could do with more progressive pedal action. Experience the air suspension in all three available settings, and you will invariably wonder why not even the comfort mode provides a satisfactory level of compliance. At the end of the third day, the S8 was perceived by all four of our testers as a cold technocrat that takes particular pride in keeping its driver at arm’s length. As best epitomized by its faultless drivetrain, this car is a somewhat empty and not entirely convincing triumph of efficiency over emotion.

Decisions, decisions. If you are a Bang & Olufsen type and love the clean Bauhaus style, Germanic perfection down to the last detail, as well as special, no-cost-spared feel-good solidity, then the S8 may be worth a second look and a first test drive. In contrast, the XJR appeals to your inner hooligan, is the secret darling of affluent hipsters, and can either play the prestige card or do donuts until a neighbor calls the cops. The S63 AMG has what it takes to be the best of all worlds, and yet it isn’t. Instead, you pay dearly for a token 0.9-second acceleration advantage over the S550.

When it was all over, we debated long and hard about crowning a winner . . . and decided there wasn’t one. Why? Because the $113,395 Audi S8 is not really that much more desirable than a 420-hp A8L 4.0T ($88,495) or even the 333-hp A8L 3.0T ($79,695). Because the $116,895 XJR makes the 470-hp XJ Supercharged ($91,495), not to mention the 340-hp XJ AWD ($78,595), look like conspicuously smart buys. Because the $140,425 S63 AMG doesn’t cast a sufficiently tall shadow to blot out the 449-hp S550 4Matic ($96,825). What we have here is, therefore, a rare case of less is more, of three oversexed and underdesirable flagship sedans, of half-kept promises and transitory illusions.

Even though the Audi has the best fit and finish, the classiest instruments, the most tasteful interior, and the brightest headlights, the four rings don’t signify perfection in every respect.

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